linux-kernel - [PATCH v3 01/15] md/raid5: Make logic blocking check consistent with logic that blocks

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Date:   Thu, 16 Jun 2022 13:19:31 -0600
From:   Logan Gunthorpe <logang@...tatee.com>
To:     linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
        Song Liu <song@...nel.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Guoqing Jiang <guoqing.jiang@...ux.dev>,
        Stephen Bates <sbates@...thlin.com>,
        Martin Oliveira <Martin.Oliveira@...eticom.com>,
        David Sloan <David.Sloan@...eticom.com>,
        Logan Gunthorpe <logang@...tatee.com>
Subject: [PATCH v3 01/15] md/raid5: Make logic blocking check consistent with logic that blocks

The check in raid5_make_request differs very slightly from the logic
that causes it to block lower down. This likely does not cause a bug
as the check is fuzzy anyway (as reshape may move on between the first
check and the subsequent check). However, make it consistent so it can
be cleaned up in a subsequent patch.

The condition which causes the schedule is:

 !(mddev->reshape_backwards ? logical_sector < conf->reshape_progress :
   logical_sector >= conf->reshape_progress) &&
  (mddev->reshape_backwards ? logical_sector < conf->reshape_safe :
   logical_sector >= conf->reshape_safe)

The condition that causes the early bailout is made to match this.

Signed-off-by: Logan Gunthorpe <logang@...tatee.com>
---
 drivers/md/raid5.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 5d84bad8b854..b3d1f894f154 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5841,7 +5841,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
 	if ((bi->bi_opf & REQ_NOWAIT) &&
 	    (conf->reshape_progress != MaxSector) &&
 	    (mddev->reshape_backwards
-	    ? (logical_sector > conf->reshape_progress && logical_sector <= conf->reshape_safe)
+	    ? (logical_sector >= conf->reshape_progress && logical_sector < conf->reshape_safe)
 	    : (logical_sector >= conf->reshape_safe && logical_sector < conf->reshape_progress))) {
 		bio_wouldblock_error(bi);
 		if (rw == WRITE)
-- 
2.30.2